Domestic boilers (furnaces) and air-conditioning systems frequently fail. It would be desirable to have automated early warning of failure or impending failure, and ideally to have this information available online.
This information could be obtained directly by measuring at the boiler, or the air-conditioning unit, or communicating with any intelligence within it. However this is often not possible or desirable, not least because of the wide variety of boilers and air-conditioning units installed.
Methods and systems for “Non-Intrusive Load Monitoring” or Analytics or Disaggregation of domestic properties are known. In such systems, domestic loads are monitored for their performance and/or energy consumption, typically using current clamps and smart meters and the like.
However, such systems have their limitations when it comes to the detection of degradation in the performance of components, as the system often has no knowledge of when the boiler, or other parts of the heating or cooling system, are active or inactive.
For example, FIG. 1 shows the differentiated minute-by-minute whole-house current consumption of a property (location). The heating system start/stop events are very difficult, if not impossible to identify.
One possible solution to identify which event is the heating system being activated or switched off is to measure the current consumption over a period of days, for example shown in FIG. 2.
FIG. 2 shows the current consumption for the property over five days. As can be seen, we can start to see a step which always occurs at the same time each day (e.g. 5.30 am), which is probably the heating turning on. However, this approach only works if the heating always turns-on at a fixed time. With modern controls, heating may start at different times, depending on how cold the house is etc. So then this simple day-by-day comparison is not a reliable method of identifying, and therefore observing, the current drawn by heating system components.
We have therefore appreciated the need for a method and apparatus for detecting degradation in the performance of a boiler or air-conditioning unit that is indicative of impending failure.